1. Field of the Invention
The present invention relates to a multilayer board including a built-in chip-type electronic component and a manufacturing method thereof, and more particularly, to a multilayer board including a built-in chip-type electronic component and a manufacturing method thereof, whereby the reliability of the connection configuration between a wiring conductor in a multilayer board and a chip-type electronic component built in the multilayer board are improved.
2. Description of the Related Art
A multilayer ceramic board including a built-in electronic component is disclosed in Japanese Examined Patent Application Publication No. 06-32378 (Patent Document 1), and another multilayer ceramic board and a manufacturing method thereof is disclosed in Japanese Unexamined Patent Application Publication No. 2002-84067 (Patent Document 2).
The multilayer ceramic board including a built-in electronic component disclosed in Patent Document 1 includes a multilayer ceramic board, a chip-type electronic component accommodated within a space defined by a recessed portion or a through hole within the multilayer ceramic board, and a conductor wiring the chip-type electronic component provided between the layers or within the space of the multilayer ceramic board. Thus, the chip-type electronic component is accommodated within the space within the multilayer ceramic board, whereby a multilayer ceramic board having a desired shape is obtained without deteriorating planarity.
In the case of the multilayer ceramic board manufacturing method disclosed in Patent Document 2, functional devices, such as capacitor elements, inductor elements, resistance elements and other suitable devices, are produced using a plate-shaped sintered plate obtained by baking a ceramic functional device beforehand, and these functional devices are built in an unsintered compound layered article. The unsintered compound layered article includes a green layer as a base, a restraint layer including a hard-to-sinter material, and a wiring conductor, and when this is baked, the green layer defining a base is prevented from contracting in the main surface direction by the restraint layer. Therefore, the unsintered compound layered article can be baked in a state in which the functional devices are built in without any problems, and also the mutual diffusion of components are not caused between the functional device and the green layer defining a base, whereby the properties of the functional devices are maintained even after baking.
However, in the cases of the multilayer ceramic boards disclosed in Patent Document 1 and Patent Document 2, with an electrical connection configuration between a built-in electronic component and a wiring conductor of the multilayer board, each of the built-in electronic components and a wiring conductor provided on the multilayer board beforehand are connected at one side of either the upper portion or lower portion of the electronic component at the manufacturing stage, which causes a problem in which initial failure and deterioration in connection reliability is caused by a disconnection between the electronic component and the wiring conductor by layering offset at the time of layering or the difference between contraction behaviors at the time of baking.
In addition, as described in Patent Document 2, storing a sintered plate causes a problem in which the entire board is formed with a non-contraction process, but the conduction between the sintered plate and the wiring conductor is not sufficient.